fix(isolated-declarations): preserve readonly literal initializers by camc314 · Pull Request #19177 · oxc-project/oxc

camc314 · 2026-02-09T12:14:22Z

This is the cause of the current monitor oxc failure

TS's Behaviour:

Us Before:

Us After:

export declare class ReadonlyLiteralInitializers {

	readonly directTrue = true;
	readonly constAssertTrue = true;
	writableTrue: boolean;
}

camc314 · 2026-02-09T12:14:40Z

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codspeed-hq · 2026-02-09T12:20:07Z

Merging this PR will not alter performance

✅ 47 untouched benchmarks
⏩ 3 skipped benchmarks¹

_{Comparing c/02-09-fix_isolated-declarations_preserve_readonly_literal_initializers (02df6a1) with c/02-09-fix_isolated-declarations_commit_msg (4eadf73)}

3 benchmarks were skipped, so the baseline results were used instead. If they were deleted from the codebase, click here and archive them to remove them from the performance reports. ↩

Copilot

Pull request overview

Fixes oxc_isolated_declarations .d.ts emit to match TypeScript behavior by preserving readonly class property literal initializers (instead of converting them into literal type annotations), addressing the reported monitor failure.

Changes:

Update readonly class property emission to keep literal/as const initializers (including parens/unary/template-without-exprs cases).
Add fixtures + Insta snapshots for readonly literal initializers and a satisfies case that should still error under --isolatedDeclarations.

Reviewed changes

Copilot reviewed 5 out of 5 changed files in this pull request and generated no comments.

Show a summary per file

File	Description
crates/oxc_isolated_declarations/src/class.rs	Adds `get_literal_const_initializer` and uses it to preserve readonly literal initializers in `.d.ts` output.
crates/oxc_isolated_declarations/tests/fixtures/readonly-class-property-initializer.ts	New fixture covering readonly literal initializer shapes (parens, `as const`, unary, template).
crates/oxc_isolated_declarations/tests/snapshots/readonly-class-property-initializer.snap	Snapshot asserting `.d.ts` preserves readonly literal initializers.
crates/oxc_isolated_declarations/tests/fixtures/readonly-satisfies.ts	New fixture for readonly initializer using `satisfies` (expected to error).
crates/oxc_isolated_declarations/tests/snapshots/readonly-satisfies.snap	Snapshot asserting TS9012-style error behavior for the `satisfies` initializer case.

Comments suppressed due to low confidence (1)

crates/oxc_isolated_declarations/src/class.rs:122

After introducing get_literal_const_initializer, the else if Self::is_need_to_infer_type_from_expression(expr) { ... } else { ... } branch in the property.readonly path looks unreachable: every expression for which is_need_to_infer_type_from_expression returns false is already handled by get_literal_const_initializer. Consider simplifying this logic (e.g. remove the dead else block and/or the redundant is_need_to_infer_type_from_expression check) to avoid maintaining code paths that can never execute.

                    // Keep literal const initializers on readonly class properties to match TS d.ts emit.
                    if let Some(initializer) = self.get_literal_const_initializer(expr) {
                        value = Some(initializer);
                        None
                    } else if Self::is_need_to_infer_type_from_expression(expr) {
                        self.transform_expression_to_ts_type(expr)
                    } else {
                        if let Expression::TemplateLiteral(lit) = expr {
                            value = self
                                .transform_template_to_string(lit)
                                .map(Expression::StringLiteral);
                        } else {
                            value = Some(expr.clone_in(self.ast.allocator));
                        }
                        None
                    }

graphite-app · 2026-02-10T02:05:56Z

Merge activity

Feb 10, 2:05 AM UTC: Dunqing added this pull request to the Graphite merge queue.
Feb 10, 2:13 AM UTC: Merged by the Graphite merge queue.

…19177) This is the cause of the current monitor oxc failure TS's Behaviour: ![Screenshot 2026-02-09 at 12.18.51.png](https://app.graphite.com/user-attachments/assets/858f029d-5427-4593-95c1-ae5efd3239e1.png) Us Before: ![Screenshot 2026-02-09 at 12.18.17.png](https://app.graphite.com/user-attachments/assets/a4df3235-e4cd-4526-b632-df7371181922.png) Us After: ``` export declare class ReadonlyLiteralInitializers { readonly directTrue = true; readonly constAssertTrue = true; writableTrue: boolean; } ```

### 💥 BREAKING CHANGES - 2bf7293 mangler: [**BREAKING**] Enable `top_level` by default for modules and commonjs (#18278) (sapphi-red) - 48b0542 span: [**BREAKING**] SourceType::ts should set module to unambigious (#18873) (Boshen) ### 🚀 Features - 500d071 minifier: Local traverse ctx and generated minifier traverse (#19106) (Boshen) - 142a1be parser: Detect binary files with TS1490 error (#19047) (Boshen) - e316857 allocator/bitset: Add `Ones` iterator to `BitSet` (#19027) (sapphi-red) - 742ad3f minifier: Default `invalid_import_side_effects` to `false` (#18916) (sapphi-red) - 0eff6be parser: Error JSX-like type assertions and generics in `.mts`/`.cts` (#18910) (Boshen) - 18320c6 span: Store file extension in `SourceType` (#18893) (Boshen) ### 🐛 Bug Fixes - a7514e4 isolated-declarations: Preserve const context in literal type inference (#19178) (camc314) - 312e756 isolated-declarations: Preserve readonly literal initializers (#19177) (camc314) - d0ca8d0 isolated-declarations: Skip parenthesis when inferring type (#19176) (camc314) - 110c300 oxc_ecmascript: `+[false]` and `+[true]` should evaluate to `NaN` (#19174) (copilot-swe-agent) - f32ea19 semantic: Report redeclaration error for import bindings conflicting with value declarations (#19068) (Boshen) - 3aeba7a semantic: Report redeclaration error for `function a() {} var a` in module mode (#19041) (Boshen) - 35e32c6 coverage: Match Babel's options.json inheritance for test fixtures (#19002) (Boshen) - 463d60d semantic: Skip TS2391 for standalone computed-name class methods (#19025) (Boshen) - 56c086b parser: Add modifier ordering validation (TS1029) (#19024) (Boshen) - 6067a49 linter/jsdoc: False positive in `check-tag-names` for `@` in email addresses and npm scopes (#19021) (Boshen) - b13bb70 semantic/jsdoc: Inline tags like `{@link}` break jsdoc parsing (#19019) (Boshen) - e3609e3 regular_expression: Preserve UnicodeEscape CharacterKind in string literals (#18998) (Boshen) - 57917ee parser: Parse decorators on rest parameters (#18938) (Boshen) - 487601b napi: Disable mimalloc on Windows to fix worker_threads crash (#18923) (Boshen) - 1f6b193 parser: Validate TypeScript import type options (#18889) (Boshen) - 1663184 parser: Allow conditional types in function type parameters (#18886) (Boshen) - 5758046 parser: Error on property access after instantiation expression (#18887) (Boshen) - 5eb4a94 parser: Handle `<<` as two `<` tokens in type argument contexts (#18885) (Boshen) ### ⚡ Performance - ed8c054 oxc_str: Add precomputed hash to Ident for fast HashMap lookups (#19143) (Boshen) - d4a0867 transformer_plugins: Switch ReplaceGlobalDefines from Traverse to VisitMut (#19146) (Boshen) - 9eb16b3 syntax: Pack ASCII identifier tables into single bitflag table (#19088) (Boshen) - e7595d1 mangler: Use BitSet for exported symbols set (#19023) (sapphi-red) - 2537924 semantic: Optimize scope resolution with fast paths and inlining (#19029) (Boshen) - 69a8d85 mangler: Use BitSet for keep_names symbols set (#19028) (sapphi-red) - f78c525 parser: Try hybrid parsing for jsx children and closing element/fragments (#18789) (camchenry) Co-authored-by: camc314 <[email protected]>

### 💥 BREAKING CHANGES - 2bf7293 mangler: [**BREAKING**] Enable `top_level` by default for modules and commonjs (oxc-project#18278) (sapphi-red) - 48b0542 span: [**BREAKING**] SourceType::ts should set module to unambigious (oxc-project#18873) (Boshen) ### 🚀 Features - 500d071 minifier: Local traverse ctx and generated minifier traverse (oxc-project#19106) (Boshen) - 142a1be parser: Detect binary files with TS1490 error (oxc-project#19047) (Boshen) - e316857 allocator/bitset: Add `Ones` iterator to `BitSet` (oxc-project#19027) (sapphi-red) - 742ad3f minifier: Default `invalid_import_side_effects` to `false` (oxc-project#18916) (sapphi-red) - 0eff6be parser: Error JSX-like type assertions and generics in `.mts`/`.cts` (oxc-project#18910) (Boshen) - 18320c6 span: Store file extension in `SourceType` (oxc-project#18893) (Boshen) ### 🐛 Bug Fixes - a7514e4 isolated-declarations: Preserve const context in literal type inference (oxc-project#19178) (camc314) - 312e756 isolated-declarations: Preserve readonly literal initializers (oxc-project#19177) (camc314) - d0ca8d0 isolated-declarations: Skip parenthesis when inferring type (oxc-project#19176) (camc314) - 110c300 oxc_ecmascript: `+[false]` and `+[true]` should evaluate to `NaN` (oxc-project#19174) (copilot-swe-agent) - f32ea19 semantic: Report redeclaration error for import bindings conflicting with value declarations (oxc-project#19068) (Boshen) - 3aeba7a semantic: Report redeclaration error for `function a() {} var a` in module mode (oxc-project#19041) (Boshen) - 35e32c6 coverage: Match Babel's options.json inheritance for test fixtures (oxc-project#19002) (Boshen) - 463d60d semantic: Skip TS2391 for standalone computed-name class methods (oxc-project#19025) (Boshen) - 56c086b parser: Add modifier ordering validation (TS1029) (oxc-project#19024) (Boshen) - 6067a49 linter/jsdoc: False positive in `check-tag-names` for `@` in email addresses and npm scopes (oxc-project#19021) (Boshen) - b13bb70 semantic/jsdoc: Inline tags like `{@link}` break jsdoc parsing (oxc-project#19019) (Boshen) - e3609e3 regular_expression: Preserve UnicodeEscape CharacterKind in string literals (oxc-project#18998) (Boshen) - 57917ee parser: Parse decorators on rest parameters (oxc-project#18938) (Boshen) - 487601b napi: Disable mimalloc on Windows to fix worker_threads crash (oxc-project#18923) (Boshen) - 1f6b193 parser: Validate TypeScript import type options (oxc-project#18889) (Boshen) - 1663184 parser: Allow conditional types in function type parameters (oxc-project#18886) (Boshen) - 5758046 parser: Error on property access after instantiation expression (oxc-project#18887) (Boshen) - 5eb4a94 parser: Handle `<<` as two `<` tokens in type argument contexts (oxc-project#18885) (Boshen) ### ⚡ Performance - ed8c054 oxc_str: Add precomputed hash to Ident for fast HashMap lookups (oxc-project#19143) (Boshen) - d4a0867 transformer_plugins: Switch ReplaceGlobalDefines from Traverse to VisitMut (oxc-project#19146) (Boshen) - 9eb16b3 syntax: Pack ASCII identifier tables into single bitflag table (oxc-project#19088) (Boshen) - e7595d1 mangler: Use BitSet for exported symbols set (oxc-project#19023) (sapphi-red) - 2537924 semantic: Optimize scope resolution with fast paths and inlining (oxc-project#19029) (Boshen) - 69a8d85 mangler: Use BitSet for keep_names symbols set (oxc-project#19028) (sapphi-red) - f78c525 parser: Try hybrid parsing for jsx children and closing element/fragments (oxc-project#18789) (camchenry) Co-authored-by: camc314 <[email protected]>

…xc-project#19177) This is the cause of the current monitor oxc failure TS's Behaviour: ![Screenshot 2026-02-09 at 12.18.51.png](https://app.graphite.com/user-attachments/assets/858f029d-5427-4593-95c1-ae5efd3239e1.png) Us Before: ![Screenshot 2026-02-09 at 12.18.17.png](https://app.graphite.com/user-attachments/assets/a4df3235-e4cd-4526-b632-df7371181922.png) Us After: ``` export declare class ReadonlyLiteralInitializers { readonly directTrue = true; readonly constAssertTrue = true; writableTrue: boolean; } ```

### 💥 BREAKING CHANGES - 2bf7293 mangler: [**BREAKING**] Enable `top_level` by default for modules and commonjs (oxc-project#18278) (sapphi-red) - 48b0542 span: [**BREAKING**] SourceType::ts should set module to unambigious (oxc-project#18873) (Boshen) ### 🚀 Features - 500d071 minifier: Local traverse ctx and generated minifier traverse (oxc-project#19106) (Boshen) - 142a1be parser: Detect binary files with TS1490 error (oxc-project#19047) (Boshen) - e316857 allocator/bitset: Add `Ones` iterator to `BitSet` (oxc-project#19027) (sapphi-red) - 742ad3f minifier: Default `invalid_import_side_effects` to `false` (oxc-project#18916) (sapphi-red) - 0eff6be parser: Error JSX-like type assertions and generics in `.mts`/`.cts` (oxc-project#18910) (Boshen) - 18320c6 span: Store file extension in `SourceType` (oxc-project#18893) (Boshen) ### 🐛 Bug Fixes - a7514e4 isolated-declarations: Preserve const context in literal type inference (oxc-project#19178) (camc314) - 312e756 isolated-declarations: Preserve readonly literal initializers (oxc-project#19177) (camc314) - d0ca8d0 isolated-declarations: Skip parenthesis when inferring type (oxc-project#19176) (camc314) - 110c300 oxc_ecmascript: `+[false]` and `+[true]` should evaluate to `NaN` (oxc-project#19174) (copilot-swe-agent) - f32ea19 semantic: Report redeclaration error for import bindings conflicting with value declarations (oxc-project#19068) (Boshen) - 3aeba7a semantic: Report redeclaration error for `function a() {} var a` in module mode (oxc-project#19041) (Boshen) - 35e32c6 coverage: Match Babel's options.json inheritance for test fixtures (oxc-project#19002) (Boshen) - 463d60d semantic: Skip TS2391 for standalone computed-name class methods (oxc-project#19025) (Boshen) - 56c086b parser: Add modifier ordering validation (TS1029) (oxc-project#19024) (Boshen) - 6067a49 linter/jsdoc: False positive in `check-tag-names` for `@` in email addresses and npm scopes (oxc-project#19021) (Boshen) - b13bb70 semantic/jsdoc: Inline tags like `{@link}` break jsdoc parsing (oxc-project#19019) (Boshen) - e3609e3 regular_expression: Preserve UnicodeEscape CharacterKind in string literals (oxc-project#18998) (Boshen) - 57917ee parser: Parse decorators on rest parameters (oxc-project#18938) (Boshen) - 487601b napi: Disable mimalloc on Windows to fix worker_threads crash (oxc-project#18923) (Boshen) - 1f6b193 parser: Validate TypeScript import type options (oxc-project#18889) (Boshen) - 1663184 parser: Allow conditional types in function type parameters (oxc-project#18886) (Boshen) - 5758046 parser: Error on property access after instantiation expression (oxc-project#18887) (Boshen) - 5eb4a94 parser: Handle `<<` as two `<` tokens in type argument contexts (oxc-project#18885) (Boshen) ### ⚡ Performance - ed8c054 oxc_str: Add precomputed hash to Ident for fast HashMap lookups (oxc-project#19143) (Boshen) - d4a0867 transformer_plugins: Switch ReplaceGlobalDefines from Traverse to VisitMut (oxc-project#19146) (Boshen) - 9eb16b3 syntax: Pack ASCII identifier tables into single bitflag table (oxc-project#19088) (Boshen) - e7595d1 mangler: Use BitSet for exported symbols set (oxc-project#19023) (sapphi-red) - 2537924 semantic: Optimize scope resolution with fast paths and inlining (oxc-project#19029) (Boshen) - 69a8d85 mangler: Use BitSet for keep_names symbols set (oxc-project#19028) (sapphi-red) - f78c525 parser: Try hybrid parsing for jsx children and closing element/fragments (oxc-project#18789) (camchenry) Co-authored-by: camc314 <[email protected]>

github-actions bot added A-isolated-declarations Isolated Declarations C-bug Category - Bug labels Feb 9, 2026

This was referenced Feb 9, 2026

fix(isolated-declarations): skip parenthesis when inferring type #19176

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fix(isolated-declarations): preserve const context in literal type inference #19178

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camc314 assigned Dunqing Feb 9, 2026

camc314 marked this pull request as ready for review February 9, 2026 12:21

camc314 requested a review from Dunqing as a code owner February 9, 2026 12:21

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Boshen mentioned this pull request Feb 10, 2026

release(crates): oxc v0.113.0 #19210

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release(crates): oxc v0.113.0 #19215

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fix(isolated-declarations): preserve readonly literal initializers#19177

fix(isolated-declarations): preserve readonly literal initializers#19177
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Merging this PR will not alter performance

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